This invention relates to a needle guard. More particularly this invention relates to a needle guard which encloses a sharpened needle edge either during the procedure for inserting a catheter or the like in a patient or upon removal of a sharpened needle after use from a patient.
As is well known, one major problem with hypodermic needles is the threat of cutting oneself or another person thereby potentially exposing blood to the environment. This has become especially important in a hospital atmosphere where AIDS patients or AIDS members of a staff can infect others by having their blood exposed and interact, for example by touching another person.
Various techniques have been proposed to overcome this problem. For example, in some cases, use has been made of a shield or cap which is placed over a needle after use. Generally, this is intended to only allow a one time use of the needle with an automatic covering system which prevents further use. However, during actual use of such a needle the needle does not remain totally protected. Further, if the needle is reused, there is no provision to sheath the needle.
Retractable syringe type needles are based on retracting the needle into the syringe upon completion of a fluid infusion procedure. A major problem with these types of products concerns the exit of the needle from the patient""s skin. From the point of removal of the needle from the skin until the needle sharpened point enters the syringe barrel it is exposed to the environment with potential for needle sticks. There is also no provision for being able to switch needles on the syringe, that is one for infusing the fluid into the syringe, and a second for infusion into the patient. This is a very common practice.
U.S. Pat. No. 4,629,453 describes a protection device for a hypodermic needle which uses a protective cap which can be fitted over the needle when the needle is not in use.
U.S. Pat. No. 4,735,618 describes a protective enclosure for hypodermic needles which employ a cap-like needle guard which is positioned about a free end of a needle while being connected via collapsible arms to a rubber tubular sleeve mounted about a needle housing. When in use, the cap is pressed against a patient under a sufficient tbrce to cause collapsing of the collapsible arms so that the cap slides back over the needle. However, when not intended for use, any accidental pushing in on the cap can cause an inadvertent needle stick.
The subject invention is directed to a needle guard mounted on a needle cannula. This needle guard can be moved from a first position where the sharpened edge of the needle is exposed for use to a second position where the tip of the sharpened needle is substantially enclosed.
The needle guard of the subject invention consists of a plastic sleeve housing having a proximal and distal end. The proximal end includes an opening into which is secured a metal part having a central hole. This central hole is sized to be just larger than the needle cannula diameter. The distal end of the needle guard consists of a circular opening which is larger than the needle cannula diameter. Inside the needle guard at the distal end is a washer having a central hole the size of the needle cannula and a diameter smaller than the inside diameter of the needle guard housing. The needle cannula is swaged, ground, or flared at the sharpened needle end to effectively increase the outer diameter or a portion thereof. This diameter is larger than the central hole of the metal part which is affixed to the proximal section of the needle guard.
Upon placement of a catheter or like structure when blood vessel puncture is achieved by the sharpened needle, the needle guard is gripped at the finger grips and moved in the distal direction until forward motion is stopped by the interference of the increased diameter area of the needle cannula and the central hole of the metal part located at the proximal end of the needle guard. The needle guard is designed such that prior to engagement of the enlarged diameter of the needle cannula with the smaller opening of the metal part, the sharpened needle passes into the needle guard and exits the opening of the washer. The washer moves in a direction parallel to it""s surface thereby closing the tip portion of the needle guard and locking the sharpened needle within the needle guard.
The action is similar when an exposed needle is removed from a patient. At that time, the needle guard is moved forward to entrap the sharpened needle.
When used as an introducer needle (Seldinger technique), the guide wire after placement of the needle in the patient blood vessel is threaded through the needle into the blood vessel as conventional. The needle is removed from the patient and the needle guard immediately positioned over the needle tip. As the needle guard is now over the sharpened edge of the needle cannula, the user is protected from an inadvertent needle stick. However, the guide wire may continue to be threaded through the introducer needle similar to what is normally done when no safety guard is attached.
In another embodiment of this invention, the needle is conventional. At the proximal end of the plastic housing is secured a corrugated sleeve which in the pleated state has a central hole. The sleeve is threaded through the needle thereby opening up the corrugations. The last corrugation (pleat) is attached to the needle hub using a metal ring or other fastening device. The movement and locking of the needle within the plastic housing is similar to the embodiment previously described.
Accordingly, it is an object of this invention to provide a needle assembly with a protective needle guard to prevent needle sticks.
It is another object of this invention to provide a method for upsetting the needle cannula to achieve an enlarged section to act as a forward stop for the needle guard.
It is another object of this invention to provide a means for allowing a guide wire to be threaded through a sharpened needle in a xe2x80x9csafexe2x80x9d condition.
It is an alternate another object of this invention to provide a corrugated strip whose axis is the needle and is strong and resilient to achieve the locking qf the needle tip within the plastic housing.